Insulin-dependent diabetes mellitis (IDDM) is a debilitating, chronic, cell-mediated autoimmune disease characterised by lymphocytic infiltration of the pancreatic islets and T lymphocyte-mediated mediated destruction of insulin-producing β cells (1, 2).
Non-obese diabetic (NOD) mice are a valuable model in studying IDDM as they spontaneously develop the disease which has many immunological and pathological similarities to human IDDM (3, 4).
It has been previously shown that administration of Freund's complete adjuvant (CFA) or Mycobacterium bovis (Bacillus Calmette-Guerin (BCG) [3]) prevents development of diabetes in NOD mice (5, 6). However, Baxter et al (7) showed the administration of BCG, although preventing diabetes in NOD mice, precipitated a syndrome similar to systemic lupus erythematosus (SLE), precluding its use in humans.
In accordance with the present invention, it has been shown that a subunit complex from the cell wall of Mycobacterium prevents diabetes in NOD mice without risk of precipitating SLE. The subunit complex, or one or more of its components, are useful, therefore in immunomodulatory therapy for autoimmune diseases and for enhancing an immune response to various cancers.